JSON Validator
Check whether your JSON is valid as you type, and pinpoint exactly where any error is. Your code is processed as text in your browser — it is never executed or uploaded.
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What does the JSON Validator do?
Validation runs on every keystroke using the native JSON parser, the same one your JavaScript code uses, so a “valid” result here means JSON.parse will succeed. Valid JSON also shows its root type, total number of values, maximum nesting depth and size in bytes.
When the JSON is invalid, the message gives the line and column and hints at likely causes.
How to use the JSON Validator
- Paste or type JSON.
- Read the ✓ valid or ✗ invalid message.
- Fix errors at the reported line and column.
- Click “Format if valid” to pretty-print it.
Examples
Invalid example
Keys in single quotes such as 'tools': 156 are reported with the position and a tip to use double quotes.
Common use cases
- Checking config files before deploying
- Validating webhook payloads
- Teaching JSON syntax
Features and benefits
- Private by design — your data is processed on your device and never uploaded.
- Free with no account, no watermark and no usage limits.
- Works on phones, tablets and desktops in any modern browser.
Limitations to know
- Checks syntax only, not a JSON Schema.
Helpful guides
Frequently asked questions
What makes JSON valid?
Double-quoted keys and strings, no trailing commas, no comments, and values that are strings, numbers, true, false, null, objects or arrays.
Does it validate against a schema?
No, it checks syntax only.
Is the data private?
Yes, it never leaves your browser.
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